Humans generally select mates based on some features that signal the potential partner's quality. Other animals are believed to use species-specific characteristics to assess and choose partners. Furthermore, like humans, age will affect this process in animals. The studies proposed in this grant would attempt to address questions as to how the age of an individual affects its attractiveness, social behavior, reproductive behavior, and fecundity. The PI proposes to use meadow voles as the model to answer the following questions: 1) Does aging affect the attractiveness of an animal's scents to opposite-sex conspecifics? 2) Does aging affect an animal's responses to the odors of conspecifics? 3) Are the age-related changes in both an animal's responses (sensory and perceptual mechanisms) and the attractiveness of its scent (stimulus) complementary, which would suggest that they may have co-evolved? 4) Does aging affect an animal's latency to mate and its mating and reproductive success? 5) Does aging affect whether or not animals self-groom (a form of odor communication)? 6) Does the age of a vole affect its scent-marking and scent counter-marking (a competitive form of odor communication) behavior? 7) Does the age of a vole affect its social status as indicated by differences in scent-marking and scent counter-marking patterns? 8) Does age of an individual affect its hormonal milieu and are such changes correlated with observed changes in the individual's behavior and reproduction? Data from the proposed studies may provide evidence suggesting that age-related effects on reproduction in the long- and short-lived animals are similar.